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DIY DE "Diatomaceous Earth" filter. (Memoirs of a filter junkie)

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28K views 35 replies 12 participants last post by  Tiger15  
#1 · (Edited)
Preface: I setup my first aquarium when I was about 12 yo using a broken tank from my middle school science teacher that I repaired myself. It was one of those great metal cornered tanks. From the very beginning I always wanted "More Filtration"! Fast forwards 30 years and several tanks someone gave me their old Vortex D1 DE filter. It turned my tank from a cloudy murky mess into a crystal clear beauty... I was hooked.

My first DIY DE filter: Unfortunately the Vortex D1 filter would clog after running it for about 5 days straight depending on water conditions and worst of all would suck down the electrons due to a very inefficient motor driving the pump. There had to be something better. After tons of reading and research I ended up with a Hayward EC40 DE pool filter (the big cylinder in the following picture).




In the front row with the black pond tubing wrapped around it is the original Vortex DE filter.

The Hayward DE filter was the best filter I have ever used. It kept my over stocked 110g cichlid perfect clear. It was pared with the trickle sump on the far right which gave gobs of biological filtration and kept the water full of oxygen. If anyone wants to build a sump I would highly recommend copying this simple effective sump design!

My 12 yo daughter has been bugging me for almost a year to setup a tank because she wants fishies! A couple weeks ago I brought the hex tank up from the storage room and set it up as a dirt under gravel planted tank. The initial fill went great but the water quickly turned brown with tannins. During our first water change we had a mishap and blasted the organic soil up through the gravel for a near water blackout! At that point I hauled the old Hayward EC40 DE filter upstairs and had the water crystal clear in about an hour. My love for DE filters was refreshed! BUT for some reason my daughter doesn't think a pool filter in the middle of our great room is appropriate... crazy kids! I relented and started planning a DE filter that would fit through the narrow 11" door on the stand and this is what I came up with...

DIY DE filter: Bigger than the Vortex but smaller than the pool filter I decided to use a whole house (Big Blue) cartridge filter I had lying around. I had a new 30 micron filter cartridge packed away with it so I decided to start there. The whole setup is very easy. Tank -> pump -> filter cartridge -> tank. Loading the cartridge is very easy, I just slowly dump pool filter diatomaceous earth directly into the intake in the tank. The pumps sucks the DE up with the water and quickly coats the filter cartridge.





Things I have learned over the years about 24x7 DE filters.
1) You really don't need a big pump. When I started with the EC40 I originally put an 1/4hp Little giant pump. Then I down sized to the 1/8hp Little Giant pump in the picture. Then I further downsized to the little QuietOne 3000 you see on my latest DIY filter. Even on the 110g tank the QuietOne 3000 pump was more than enough flow!
2) The Diatomaceous Earth lasts a LONG time! On my very dirty 110g cichlid tank I went 5 years, 24x7x365 without EVER changing the DE!!!! When the flow would start to slow I would turn off the pump, pump the handle on the filter to knock all the DE off the filter screens then turn the pump back on. A little DE bloom would hit the water but the filter would clear up up in no time.
3) The EC40 is not the perfect fish tank filter. The one downside of the EC40 is that I could never get it 100% sealed and leak free. It would leak about 1/4 cup of water a day. I kept in a rubbermaid container and the water would evaporate fast enough that I would never have to empty it.
4) Pool DE media is REALLY cheap and from what I can tell is identical to the expensive Vortex DE powder! 5 years and the fish never hay and health issues. From what I read DE will filter out parasites like Ich which makes it a perfect fish tank filter media.
5) I thought I would need a higher pressure pump to compensate for the much smaller surface area on the big blue cartridge filter. I started with the LittleGiant 1/8hp high pressure pump on my latest DIY filter. It was too strong, it worked but I had to do put a strainer on the output into the tank to break up the heavy stream. The QuietOne 3000 pump is working perfectly!
6) A simple sponge on the intake in the tank makes a perfect prefilter to catch the big chunks. The sponge takes about a minute to pull, wash and replace.
7) When the pump is turned off most of the DE falls to the bottom of the filter. IT IS MUCH BETTER TO RUN THE CANISTER FILTER UPSIDE DOWN! When the pump starts the water stream will push the DE up from the upside down top of the cartridge filter and it will cover the filter cartridge much faster and more evenly!



A long time ago I drilled this tank and used a sump with it. I repurposed the overflow as an intake and it is working very well. The elbow is positioned so the sponge catches debree from the water surface.

Our tank is cycling well and the plants seem to be happy... when my daughter is back with my next week we will add our first guppies! I plan on building a hood for the tank with a light in it... another good project for my daughter and me.

I am also planning on mounting the cartridge filter, pump and an inline filter on a board that will fit into the cabinet as a single unit that I can remove for servicing. The current manifold on the pump has an extra spigot to east water changes. I think the manifold will be redesigned a bit in the final version. Right now I am seeing how long the 10" x 2.5" filter cartridge will last before it has to be rinsed and recharged. Big Blue also makes a 20" x 4.5" cartridge filter with obviously will have much more filter area. If the little 10" x 2.5" doesn't last very long I will extrapolate how long a bigger cartridge should last and consider upgrading.
 
#4 ·
Sorry, I was in the middle of posting when the power blipped. When my computer came back the start of the post had already been posted. :)

Bump:
Hi Oughtsix,

$250; 38 gallons per minute.....what a beast!

BTW, when I have a cloudy water issue I use the Marineland 350 Magnum with the micron filter and add some DE. I do remember the Vortex filters and I think they still make them but you are right the flow dropped fairly quickly in a dirty tank.
Yep, that is the beast! I included some of my other filters in the picture as a size comparison. If you look closely you will see a Magnum 350 in there along with an original Vortex D1. If it isn't obvious I love DE filters. I know the DE will support a colony of beneficial bacteria but I am hopping to keep as much BB in the tank and only have mechanical filtration.
 
#3 ·
Hi Oughtsix,

$250; 38 gallons per minute.....what a beast!

BTW, when I have a cloudy water issue I use the Marineland 350 Magnum with the micron filter and add some DE. I do remember the Vortex filters and I think they still make them but you are right the flow dropped fairly quickly in a dirty tank.
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#5 · (Edited)


Here is a close up of the intake. It is working well. As you can see the return is temporary... I am not sure how I want to do the return yet???? I am thinking a spray bar but I am open to suggestions!?!?!?!?



I don't know if you can tell from this picture but the water is very clear... with a yellow tinge to it from the tanins leaching out of the soil.
 
#6 ·
The Vortex is still made. The thing about a DE filter is it is used to "polish" the water, not as a continuous filtering device. It filters down to 1 micron.
I've still got my original one I bought back in the early 80s.
If you need to run a DE filter 24/7/365 you're doing something wrong.

If you grind up some activated carbon in an old coffee grinder and charge the filter with it it will even remove organics post haste.
 
#10 · (Edited)
If you need to run a DE filter 24/7/365 you're doing something wrong.
DE filters are simply extremely effective mechanical filters. The Vortex Diatom filters were designed for occasional water polishing, why should that preclude DE being used in a 24/7/365 filtration system? DE filters do much more than just make the water look pretty, they also remove pathogens making the water and aquatic environment healthier! DE filters run in swimming pools 24/7/365 why not an aquarium? DE filters are so safe they are also frequently used to filter beer.

By your reasoning wouldn't running any filter 24/7/365 mean you are doing something wrong?


If you grind up some activated carbon in an old coffee grinder and charge the filter with it it will even remove organics post haste.
To me carbon is a crutch to lean on when something is out of balance in your aquarium. If I had a problem in my tank and I needed to quickly chemically filter the water powdered charcoal would do an excellent job. I would not want to contaminate the DE media with powdered carbon on a routine basis. The carbon will loose its effectiveness before the DE will loose its effectiveness.
 
#8 · (Edited)
When I was running the big EC40 I had it positioned after the trickle filter. I washed the sponge in the trickle filter periodically and that removed most the big solids. The EC40 removed all the small stuff. This was in a tank without AQUATIC plants. Yes, debris would build up in the EC40 and after 5 years it must have decomposed... which would add significantly to Nitrates. I had a very effective Nitrate filter in a jungle of terrestrial Pothos plants.

The trickle filter removed the large debris and had the capacity to maintain a huge beneficial bacteria (BB) colony with the water dripping over the bio balls and an air stone underneath the bio balls constantly supplying fresh oxygenated air.

The EC40 trapped the minute debris (and free floating algae and fungus and parasites) and I am confident also maintained a healthy BB colony.

Between the trickle filter and the EC40 I had a very effective biological filter for breaking waste down to Nitrates. I had a large amount of terrestrial Pothos that loved the nitrates and sucked them up using them to grow.

The maintenance on the system was monthly water changes, clearing the sponge in the trickle filter, refreshing the DE in the EC40 and LOTS of Pothos trimming! My ammonia and nitrite levels were basically null. Nitrate levels stayed very low due to the Pothos. The water had an abundance of O2 thanks to the water stream being broken down to droplets by the bioballs with an air stone underneath them. The fish were very healthy, happy and I never had any kind of disease or parasite... everything was great until the 110g sprung a leak!

I enjoy the science of filtration and engineering a healthy minimal maintenance tank almost more than I enjoy the fish. :) My goal with my new tank is to setup a new balanced ecosystem using aquatic plants instead of the terrestrial Pothos plants... hence why I am here... to learn!


I will post separately about the DE filter mechanics and maintenance.
 
#11 · (Edited)
:) Glad you asked! Definitely! Way back when... I tried many whole house filters of different grid sizes. The spun filament 5 micron whole house filter cartridges also produce beautiful water... for about a day. To get more than a days use out of them your need a pretty high pressure pump. Way back when I was experimenting with whole house filter cartridges I was running 3 x spun filament 5 micron cartridge filters in parallel (to triple the effective filtering area). I finally upgraded to a high pressure 1/4 hp pump to supply the needed pressure. I was devastated when I came home the first day after implementing the pump... all my fish were floating on the top of the water. The filter was functioning, the water was perfectly clear... but the water temperature was 130 degrees F. The heat from the pump and the heat induced in the water from the high pressure boiled my fish. I didn't have a tank for about 5 years after that incident.

In the lower right of my first picture you can see an Ocean Clear cartridge filter made specifically for salt water tanks (I have never ventured into salt water myself). The Ocean Clear filter cartridge has a MUCH larger surface area than a 2.5" x 10" whole house filter cartridge. With a prefilter I could get a week out of that filter before it needed to be cleaned and I think the cartridge was about 50 micron so it didn't clean the water anywhere near as well as a DE filter. I also could never get the Ocean Clear filter completely sealed and to stop leaking.

The advantage of a DE filter is the Diatomatous Earth offers a HUGE filtering area and a very small pore size. It filters very small particles and takes a long time to plug. The coat of DE on the filter screen is many thousands of layers thick. When the DE does plug you can simply turn off the pump, knock the DE off the filter screen then turn the pump back on to recoat the filter screen with a fresh layer of DE exposed.

In the EC40 there is a big handle on top. Actuating this handle knocks the DE off the internal filter screens. When you turn the pump back on the filter screens recoat with a fresh layer of DE exposed and you are back to full flow. This is how I was able to get 5 years out of one charge of DE media! The intake on the EC40 is at the very bottom of the tank so the incoming water stream disperses the DE media and evenly coats the filter screen... this is where I got the idea to run the whole house filter upside down so the incoming water stream disperses the DE media in the whole house filter.

For my whole house DE filter I plan to turn off the pump, shake the filter to knock the DE media off the filter cartridge then turn the pump back on with the whole house filter upside down. I will keep updating this thread as I get useful data on the life of the DE media.
 
#15 ·
I still don't understand. If you never physically remove the contaminants, when you knock it down, it could very easily bypass the (now not present) filter and now need to be refiltered out.. right?

I get how you can never need to change the media with this method but im sorry I just don't understand how this benefits the aquarium without replacing the media, or, filtering the filterr so to speak
 
#17 ·
I still don't understand. If you never physically remove the contaminants, when you knock it down, it could very easily bypass the (now not present) filter and now need to be refiltered out.. right?

I get how you can never need to change the media with this method but im sorry I just don't understand how this benefits the aquarium without replacing the media, or, filtering the filter so to speak
Diatoms are microscopic little creatures that live in shells. When the Diatom dies it leaves an empty shell with microscopic holes in it. Billions of these Diatom shells are what constitutes diatomaceous earth. When the filter screen is coated with DE there are thousands if not tens of thousands of layers of these empty Diatom shells. When a piece of microscopic debris comes into the filter it gets trapped in a pore of one of these empty shells. After about a month enough of the empty shells on the surface layer of the DE get plugged that they slow the flow of water. By turning off the pump and shaking the filter screens you knock off all of the thousands layers of DE from the filter screen. When the pump is turned back on the diatom shells get suspended in the water stream and accumulate on the filter screen. Some of the shells will pass through the filter screen and you will get a small white cloud in your tank but these shells get sucked back into the filter and end up on the outside of the coat of DE on the filter screens.

Any large accumulated debris will be packed in the layer of DE coating the filter screen. If the debris is organic it will be eaten up by bacteria and be digested to ammonia -> nitrites -> nitrates. You need to have some way to effectively remove the nitrates from the tank. This could be water changes or it could be plants feeding on the nitrates. If you do not have some way to remove the nitrates from your tank they will build up to toxic levels.

When I started my current dirt floor 35g hex tank we had a mishap with a water change that turned the tank water into mud. I put the EC40 on the tank and water was perfectly clear in under an hour. When I knocked off the DE inside the EC40 and restarted the pump there was a small white cloud of DE that dissipated very quickly was it was re-assimilated by the filter.


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In my 110g cichlid tank I used Pothos plants to remove the Nitrates. In our new 35g dirt planted tank we hope the aquatic plants will convert the nitrates into plant matter. The DIY DE filter is there to filter out visible and microscopic debris from the water. The pores in the DE shells are so small they will also filter out free floating algae and pathogens like Ich and other parasites. This makes for a very healthy tank.

Does this make more sense to you now?... did I do a decent job explaining it?
 
#16 ·
I'm remembering using the Vortex diatom filter back in the 70's, but only periodically to polish the water. I don't know what ever happened to it.
FWIW I think it's overkill to run a diatom filter continuously when you can have crystal clear water with regular filtration and good tank maintenance.
These days for periodic water polishing I use a Marineland Magnum Internal Canister Polishing Filter. It's like the Magnum 350 except it's the newer internal model. I've used it with DE but it tends to spit some DE when it restarts in the tank so I typically just use it with the micron cartridge alone - works great. I tend to use it for a few hours after a water change/tank maintenance just to give the water an extra polish, removing algae particles I've scraped of the glass and any 'no-see-ums organic particles'.
 
#19 ·
I like my tank water very clear... all the time! When I ventured over to the Fish forum on this site and read about all the Ich problems I decided a DE filter was a must and would be my main and only tank filter.

I love the Eheim filter in my first picture. It is one of the only filters I have purchased new and it has always done a great job for me. No matter what media I put into it the Eheim never gets my water as close to clear as a DE filter does. The Magnum 350 with the micro cartridge doesn't come close to DE clarity either and I doubt the cartridge will filter out pathogens?

I personally do not see any reason NOT TO run a DE filter 24x7x365? Its benefits are great and I haven't really found a downside after running a DE filter 24x7x365 for many years. I haven't found a filter with lower running/maintenance costs. (The Quiet One 3000 pump is rated at 49 watts which is lower than my canister filters and I have a 10 lifetime supply of DE that I paid $30 for).

I don't "plan" on running a bio filter. Not everyone wants a DE filter, I understand that. I thought I would present it as an option and share my ongoing experiences. :smile2:
 
#21 ·
I completely understand the theory behind what your saying, and DE filter mechanics and operation completely.

If what you were saying was true, you would never need to shake down the filter. But because it cannot keep up due to mechanical limitations, being ccloggd.

you have too address the issue by cleaning the media or replacing it and you said you simply cycle power on the filter, renewing the cake.

The end result is the cloud of debris, that you need to refilter.

Im not against de filters but they need to be used differently, as a sidestream filter. The media needs to be removed cleaned or discarded

My point is, if you are washing your filter out in the filter box, or water discharge to your aquarium what are you actually achieving?
 
#22 ·
In the huge EC40 on my 110g tank I can tell you that in reality there was no huge release of debris after cycling the DE media. The EC40 which is designed to filter ~20,000 gallon pools and have the DE media removed and new DE media introduced once or twice a year lasted 5 years on my 110g tank without having to change the DE media and the water was always perfectly clear and the fish healthy. I think of the EC40 as being akin to filling my house with filter sponges, plumbing the outflow of my 110g tank to the basement then returning the water that comes out the chimney back to my 110g tank. Eventually those sponges will need replacing... but it may take several years.

In my new DIY DE filter I do not know what the practical life expectancy of the DE media will be. I do not know how long it will take for the media to be clogged and need to be recycled. I do not know how long it will take until the media is so clogged that it will need to be changed... that is what I enjoy, FINDING OUT!
 
#23 ·
I feel I may have overlooked the 20,000 gallon part. It's also hard to judge not seeing it work in person. (Mechanically what happens exactly in your system)
..

I just never think it's a good idea to store more poop. Bacteria is pretty small ive had huge bio loads on small filters

Not trying to hate on your project, good job. I would just run my setup a bit different for different goals
 
#27 ·
Well it has been about 3 weeks and the DIY DE cartridge needed a cleaning and new DE media. I am actually pretty happy with the initial longevity of the first DE media charge considering I am running a very porous pre-filter and this was the initial setup of a dirt substrate tank with a LOT of fine dirt particles. The entire time the water has been exceptionally clear except for a slight yellow tint from tannins. There were definitely no detectable particles suspended in the water column.

I am seriously considering a trickle filter which would add considerable mechanical pre-filtration to the DE cartridge filter.

I am very tempted to change from the 2" x 10" cartridge filter to a 4.5" x 20" cartridge filter... but I am going to hold off and experiment with the 2" x 10" further to see what kind of life I get out of the DE media now that the tank has settled and with a decent pre-filter added.
 
#30 · (Edited)
I used to have a small Jacuzzi-brand DE filter running 24-7 on my 75 gallon hex tank. I kept the filter and pump system I designed on the floor. The motor and valves were similar to a swimming pool filter system. Aquarium shops say DE is not good for fish's gills. I say that's b.s. since my fish never had a gill problem and were always healthy including their fins. I never lost one in over a year and a half plus that tank water was always sparking. I didn't need any other filtration other than the DE filter. I only kept a few fish and did partial water changes.
 
#31 ·
Shortly after my previous post I got the filter working well with DE. Again, I'm using the Marineland Magnum Polishing Internal Canister filter with the micron cartridge and the appropriate amount of DE.
On water change day, I setup a 5g bucket to the front side of the aquarium with the filter in the bottom and the DE alongside. When I drain the tank, I fill the bucket 1st and plug in the filter to charge with DE. Then the rest of the water goes to the drain. I scrape the glass, prune plants, do filter maintenance (if needed), then refill. Following the refill, I unplug the filter, install in the tank and start it back up. I let it run for several hours. It does all I need it to do for just an extra measure of filtration....the water remains crystal clear all week (but I don't have on-going tannins.) Rereading this thread I'm intrigued by the idea of also using powdered carbon along with the DE....I just might give that a try!
 
#35 ·
It was already a tool used in keeping the aquarium clean by the Vortex Diatom Filter system .
Starting from 30 years ago, i charged the filter with d. earth and powered carbon made by Vortex. It super cleaned my system better than normal carbon/media filter system.
No particulates or chemicals or nitro waste products were in the water after about day. Crystal clear water was a result, but it was tough to clean out the filter well .
If you can't get the canister of powered carbon , maybe the wash residual of carbon can be kept to be used for this purpose.
 
#32 ·
Just thought I'd add to this since I've had a Hayward EC65 DE filter on my 22K gallon pool for about ten years. I don't mean to brag but after the first week of misery opening the pool every year, my water is world-class absolutely crystal clear. It really is amazing to go under water with a mask and look across the pool and imagine you're really looking through 33' of water. As I said, the opening is tough (doing it now) because the filter is so effective that a heavy load of algae will choke it in under an hour (even with "bumping" to reseat the DE layer) and I'll probably recharge the DE 5+ times in that week. Then, as stated previously, recharge once a month or when the tank pressure doesn't stay down. BTW, if you run a sand filter you also can have the benefits of DE by adding a cup or so in the pool skimmer, just to raise the pressure a couple psi. You'll need to replace it every time you backwash.
I'm here because I'm also starting up my 65 gallon with a couple inches of Saf-T-Sorb substrate and clearing with the Aquaclear 110 seems like abuse of a good aquarium filter. The Saf-T-Sorb has been washed several times but never really ran clear. So putting 2 and 2 together it just seemed like a good idea to try to rig up a DE filter for the fish tank. Now I'm reading it wasn't my idea. Oh well. I have found that after a couple hours of filtering, a fair amount settles to the bottom and is easily gavel vacced up.

Just a minor point of clarification: I'm pretty sure DE filters down to 5 microns, not 1. But the results, even on a larger scale are stunning.
 
#33 · (Edited)
Just a minor point of clarification: I'm pretty sure DE filters down to 5 microns, not 1. But the results, even on a larger scale are stunning.
I am still a big fan of DE filters and I am currently running a 24" big blue cartridge filter for the DE.

I discovered that there are different grades of DE with different pore sizes so some DE might filter down to 5 microns and other down to 1 micron. I am using DE meant for pool filters... if pool filter DE is typically 5 microns I'll take you word for it. I love how clear my tank water is when I use a DE filter and haven't found any other filtration that I have tested that comes any where close. I also believe that DE filtration really helps in curtailing the spread of fungus based diseases and even free floating algae in the water column... but this is purely my speculation!!! I can't imagine I would ever setup a tank without a DE filter again.

We are in the process of setting up a 180G tank... we will be using a Hayward pool filter! Fortunately a charge of DE lasts much longer filtering a 180g tank than filtering a 40,000g pool!